3.92 Gear swap

Deepc6 · Nov 20, 2017

Hello All,

I am really considering a 3.92 gear swap on my 2016 RAM 1500. Does anyone have a parts list of what is required?
I have 2016 Limited with AWD, 4 Wheel high and 4 wheel low.

Thank You in advance

2016 RAM 1500

69GWC · Nov 20, 2017

You need the rear gears and a complete front diff from what I am told.
While your at it if you dont have a lsd now is the time to install it.
Moe's is a good place for the rear parts and the dealer or junk yard for the front.

noupf · Nov 20, 2017

and your gonna be out a few thousand dollars at least. Just search the forum, its been covered a lot on here.

JosephVK56 · Nov 26, 2017

69GWC said:
You need the rear gears and a complete front diff from what I am told.
While your at it if you dont have a lsd now is the time to install it.
Moe's is a good place for the rear parts and the dealer or junk yard for the front.

why a whole front diff? i want to do a 4.56 swap, why cant we just re-gear it instead of an entire diff swap?

deangtp · Nov 26, 2017

You could go to car-part.com and buy low mileage used ones. That's what I did. I paid around 1500 for a front diff and a rear axle with the limited slip. 6,000 miles on the units. Came from the same truck

WiSH2oo0 · Nov 26, 2017

If you ever plan on lifting your truck anytime in the future, now would be the time to jack that thing to the sky. Nobody wants to fight those top three differential bolts with red loctite more then once in a lifetime. Then when you have that old front differential sitting in your driveway and a saws-all in hand getting ready to cut that front cross member. The preying begins and hoping that you measured everything right the first 3 times before the cut. Then the sparks start to fly and you're hoping that you didn't just **** up your brand new truck.

:big_banana_Dance:

Oh the fond memories and the stories you can tell. I haven't ran into anyone else yet that has installed there lift kit themselves yet.

crazykid1994 · Nov 26, 2017

JosephVK56 said:
why a whole front diff? i want to do a 4.56 swap, why cant we just re-gear it instead of an entire diff swap?

Front diff in 2013+ I think is welded. Someone correct me. Which means the gears cannot be removed and changed. Older 2010-2012 diffs I believe are what’s being used when swapping gears because they’re not welded

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bryan28 · Nov 26, 2017

It pays to do research before buying any new vehicle.

smiley · Nov 26, 2017

Anyone ever tried to torch out the old gears in the welded versions?

shadowhawk · Nov 26, 2017

or, those that didn't know gearing had different impacts learned the hard way. Honestly though, I would have still bought this truck with or without 3.92.

Wild one · Nov 26, 2017

JosephVK56 said:
why a whole front diff? i want to do a 4.56 swap, why cant we just re-gear it instead of an entire diff swap?

You'll need the earlier AAM front diff from a 09 to 2011 truck,to do a 4.56 swap.It's a ***** to install,as to do it right you'll need to swap the drivers side motor mount to,plus you'll need the earlier front driveshaft,as it's different from the later ZF's front shaft.You can fab up some brackets to hold the diff,but in the long run it's probably easier to swap motor mounts.Hang onto your wallet,as it's gonna make your ass pucker on cost to put 4.56's into your 2017

S0CAL · Nov 26, 2017

crazykid1994 said:
Front diff in 2013+ I think is welded. Someone correct me. Which means the gears cannot be removed and changed. Older 2010-2012 diffs I believe are what’s being used when swapping gears because they’re not welded

Sent from my iPhone using Tapatalk

ZF welded the ring gear to the carrier rather than using conventional ring gear bolts. To change gears in your truck, you’ll need to look at 2011 and earlier axles. Pulled this from justdifferentials.com.

I recently regeared 3:55 to 4:56 front and rear and dropped in a Detroit Trutrac LSD, no issues but I have 2010.

crazykid1994 · Nov 26, 2017

S0CAL said:
ZF welded the ring gear to the carrier rather than using conventional ring gear bolts. To change gears in your truck, you’ll need to look at 2011 and earlier axles. Pulled this from justdifferentials.com.

I recently regeared 3:55 to 4:56 front and rear and dropped in a Detroit Trutrac LSD, no issues but I have 2010.

Thank you for correcting me. I couldn’t remember for the life of me which years it was

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Deepc6 · Feb 19, 2018

This might seem naive, this is my first truck. Does the LSD refer to the front as well as the rear?

S0CAL · Feb 19, 2018

Just rear, and not naive at all.

6.7CumminsDrvr · Feb 19, 2018

Jury is still out on the welded front diff, there are folks claiming/reporting it was just on the 13’s but no one seems be able to confirm.........biggest issue with the ZF diff is there’s NO AFTERMARKET gears so no go on anything lower than 3.92’s

And this really stinks because the ZF is a high pinion unit and about 1/2” larger so overall it it much stronger

2010 Infantry Vet · Feb 19, 2018

Using an arc gouge to remove the welded gears can be done, but it has to be done by a competant person.

Deepc6 · Feb 19, 2018

What if a used from differential with 3.92 gears was installed I assume that would work. So I ha e had mix responses on the LSD does it refer to the front, rear or both gears?

Wild one · Feb 19, 2018

Deepc6 said:
What if a used from differential with 3.92 gears was installed I assume that would work. So I ha e had mix responses on the LSD does it refer to the front, rear or both gears?

That's your cheapest solution,hunt around an find a low milege wrecked 2013 or newer truck and buy both diffs if you can.The limited slip is only available in the rear on the trucks.

2010 Infantry Vet · Feb 19, 2018

Wild one said:
That's your cheapest solution,hunt around an find a low milege wrecked 2013 or newer truck and buy both diffs if you can.The limited slip is only available in the rear on the trucks.

Screw the cheap clutch pack oem lsd. Get a detroit locker or truetrac. Same damn price as the factory junk.

3.92 Gear swap

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